Mariah Carey made a tough decision on Sunday's series premiere of Mariah's World.

On the episode, Mariah was extremely busy wrapping up her Las Vegas residency, preparing for her European tour and on top of that was planning her wedding to James Packer. But, after multiple talks with her manager Stella, Mariah decided the best thing to do would be to postpone the wedding.

After making the decision, Mariah had to make the phone call to James to tell him.

The rivalry between Bianca and Mariah began in the music video, where the two have a major fight in the bathroom of a movie theater and Bianca says she would've won that brawl if she hadn't "had a cold" at the time.

LOL!

And when asked to describe Mariah, Bianca says she can't because she thinks Mariah has "done well enough on her own."

Read

Mariah needed some help putting her shoes on during the episode, so a team of four people helped her slip into her stilettos!

"Oprah told me, 'Don't let anybody think that you don't know how to put your shoes on anymore,'" Mariah reveals. "The problem is these shoes are abusive and I can't put them on alone. I'm not gonna lie about it."

Read

After their first initial talk about the wedding, Mariah and Stella sit down again and make a final decision.

"So do we postpone the wedding?" Stella asks.

"I just...I don't...I don't know because he keeps asking what we're doing with the dates and when he asks...I don't want to disappoint him and I feel really bad," Mariah says. "And so now I'm sitting here going, 'How do I even do this?'"

But Stella assures Mariah that James loves her "so much" and he'll be "supportive" of whatever she thinks is best because he "always defers" to her.

After hearing this, Mariah says, "OK, maybe we do the tour and then figure it out afterwards and do it right. You know it's not an easy call to make."

Mariah continues, "This is a hard decision to make, I'm not sitting around like, 'Oh just blow off the wedding.' I'm sitting here going, 'How am I supposed to fulfill my professional obligations and not disappoint James?'"

Read

After her phone call with James, Mariah tells Stella, "He's waiting for me to figure it out. Like when we're gonna do it, how we're gonna do it and all that."

Stella then admits, "I'm actually relieved that Mariah wants to postpone her wedding because I've been dealing with this prenup and it's definitely not the most romantic thing I've read I'll tell you that. So I feel like we should meet our professional obligations first before jumping into any personal commitments at this moment."

After making the decision Mariah says, "I feel bad because I know I've disappointed James by postponing the wedding. But what I need to focus on right now is this tour."

Read

On top of everything else she has going on, Mariah has been working hard in rehearsals to prepare for her tour and her manager Stella doesn't know how she does it all.

"I don't know how Mariah does it, to work a full day, do her engineering and then start with me at midnight and finish with me at 8 a.m.," Stella says. "She's a machine, she really is."

E!

9. Mariah & Stella Arrive Three Hours Late to Rehearsal:

With two days left until opening night of her European tour, Mariah and her squad travel to Glasgow to prepare. But unfortunately, not everything goes according to plan and Mariah and Stella end up three hours late to rehearsal because of a passport dilemma and Mariah admits she's "very stressed."

"Mariah's nanny...she packs her passport in a suitcase, she doesn't realize they collect the passports on the plane and she doesn't have hers," Stella explains. "And it took hours, waiting, to clear the nanny to get into the country, cutting into Mariah's precious rehearsal time."

"When you're going on tour and it's your name...that's what people will remember," Mariah says. "If something happened where it was somebody else's fault, they're not gonna care, it's always my fault, it doesn't matter. To the fans or the people who don't know the behind the scenes thing, it's always my fault, no one else gets blamed."

Mariah then explains, "We only have one day to get the show together, every single detail, the lighting and the screens. I believe that we can do a show, but this is 27 shows. I'm not quite sure how somebody thinks we're gonna pull this off."